napolitano and he will continue to get updates throughout the evening. again, there's not a whole lot of information in terms of who actually carried out the acts of frustration this evening because they don't know if this was carried out by someone here on u.s. soil or someone abroad. so that is really the key question they are looking into. again, president obama continuing to monitor the situation into the evening, lawrence. >> kristen welker, thank you. joining me now nbc news justice correspondent pete williams. >> lawrence, good evening. investigators know for certain that this attack involved two bombs, but what they don't know is whether there were any other explosives involved. and frankly, the information on this is confused tonight. at least five other packages found on the street were deemed to be suspicious, and were destroyed by boston police and bomb squad techs. and there were many packages to check, officials say, because after the explosions, people simply dropped what they were carrying and ran away. we have heard, quite frankly, confl